Information Technology Reference
In-Depth Information
Dynamic Routing Protocol Concepts Exercise
Perspective and Background
As networks have evolved and become more complex, new routing protocols have emerged. One of
the earliest routing protocols,
Routing Information Protocol (RIP)
, has evolved into a newer version,
RIPv2
. To address the needs of larger networks, two advanced routing protocols were developed:
Open Shortest Path First (OSPF)
and
Intermediate System-to-Intermediate System (IS-IS)
. Cisco
developed
Interior Gateway Routing Protocol (IGRP)
and
Enhanced IGRP (EIGRP)
, which also scales
well in larger network implementations.
Additionally, there was the need to interconnect different internetworks and provide routing among
them.
Border Gateway Protocol (BGP)
is now used between Internet service providers (ISP) as well as
between ISPs and their larger private clients to exchange routing information.
With the advent of numerous consumer devices using IP, the
IPv4
addressing space is nearly exhaust-
ed. Thus,
IPv6
has emerged, which has required newer versions of the IP routing protocols to be
developed.
Role of Dynamic Routing Protocols
Routing protocols determine the best
path
to each network, which is then added to the
routing
table.
One of the primary benefits of using a dynamic routing protocol is that routers exchange routing
information whenever there is a
topology change
.
Compared to static routing, dynamic routing protocols require less
administrative
overhead. However,
the expense of using dynamic routing protocols is dedicating part of a router's
resources
for protocol
operation, including
CPU
time and network link
bandwidth
.
Purpose of Dynamic Routing Protocols
A routing protocol is a set of processes,
algorithms
, and messages that are used to exchange routing
information and populate the
routing table
with the routing protocol's choice of best
paths
.
List the four purposes of a routing protocol.
Discovery of remote networks
■
Maintaining up-to-date routing information
■
Choosing the best path to destination networks
■
Ability to find a new best path if the current path is no longer available
■
List and briefly describe the main components of a routing protocol.
Data structures:
Some routing protocols use tables and/or databases for their operations. This
information is kept in RAM.
■
Algor
ithm:
An algorithm is a finite list of steps used in accomplishing a task. Routing proto-
cols use algorithms for facilitating routing information and for best-path determination.
■
Routing protocol messages:
Routing protocols use various types of messages to discover
neighboring routers and exchange routing information, and do other tasks to learn and maintain
accurate information about the network.
■
Dynamic Routing Protocol Operation
The method that a routing protocol uses to accomplish its purpose depends on the
algorithm
it uses
and the operational characteristics of that protocol.
